Transmission Slow to Grab First Started. Requires RPM's to get moving.

[777funk]

I have an E4OD in my van and I had it rebuilt a few months back. I've had all sorts of issues. But here's one I'm just now noticing. On the first startup for the day, I'll put it in drive and it's slow to grab. The engine revs but doesn't go anywhere unless I really give it some gas. It only does this on the first start of the day after that it's just fine. Any ideas what could cause this?

EDIT updated with details:
-rebuilt transmission (was originally not ever going into 4th and didn't have these other symptoms)
-new Motorcraft VSS
-new MLPS
-bigger rear tires by one size
-air bag blinks and abs light comes on occasionally
-VSS code but was driven with the sensor un-plugged for a few blocks
-fluid level ok when last checked (checked it since the problems)

[dieselcamino]

low fluid? torque converter not building enough pressure

[Mark Kovalsky]

The torque converter doesn't build pressure. The pump builds pressure and sends it to the torque converter, among other places.

I think your torque converter is draining into the pan. It's easy to check for this. Before starting the engine after it sat long enough to cause the problem, check the trans fluid level. If it is showing overfilled it's because the torque converter has drained into the pan. There is a check valve that should prevent that.

[777funk]

Originally Posted by Mark Kovalsky

The torque converter doesn't build pressure. The pump builds pressure and sends it to the torque converter, among other places.

I think your torque converter is draining into the pan. It's easy to check for this. Before starting the engine after it sat long enough to cause the problem, check the trans fluid level. If it is showing overfilled it's because the torque converter has drained into the pan. There is a check valve that should prevent that.

This sounds likely.

But there are more problems. Tonight I wired up a display (go more into this in a moment) and watched the computer commands. They did not match what the transmission was doing.

I noticed that the transmission is shifting from 1st to 4th at times. Also upon deceleration the computer showed it going to 3rd gear and the trans was not down shifting. My OD OFF light is blinking. I noticed when the T.C.C. light comes on I hear the Torque Converter engaging. When that happens I hear a flare for a second then the TC grabs.

I don't know how the Torque Converter works but it seems like it's not converting the engines energy until the T.C. Clutch locks up. The engines torque is definitely not getting transferred. Here's what is happening with the pressure... if I put it in 1ST Gear Manually it will take off MUCH better. It seems to be getting pressure when I shift manually.

Now more on my display (picture also attached):
I built a simple LED display tester to show solenoid pack status because my re-builder is saying that he thinks it's an electronic problem. So here's what I did. I purchased an E4od solenoid harness and connected the hot lead to the solenoids (12V) through a 1.5k current limiting resistor (to avoid having the 12 volts burn up the LED's) to the positive side of the LED's (one for each solenoid - S1 - S2 - TCC - CC) and the control signal (ground) to the negative lead of the respective LED for each display. So when in first gear for instance the S1 LED comes on, second S1 AND S2, third S2 ONLY, 4th Neither S1 or S2. And the TCC came on every time with 4th gear.

I noticed one thing a little strange. The Coast Clutch LED was half (as in dimly lit and not solid) on until 4th gear when the TCC locks up, then it goes off. It comes on solid (full bright) when I put it in manual 1ST gear and hit the brakes. I'm not sure what this means.

The other thing I didn't have a visual on was whatever controls line pressure. I think that's two wires labeled EPC power in the attached picture. I don't remember where the picture is from but it's very useful to understand the electrical half of the E4OD. I'm not sure what the EPC (... electronic pressure control???) voltage should be. I suppose it varies with throttle position like what a vacuum modulator did before electronic transmissions came along. I'm guessing higher voltages equal firmer shifts?

[777funk]

Just checked things a little more and measured across the solenoids.

PROBLEM... S1 is open circuit.
PROBLEM two... I don't know if this is wrong or not but across the EPC solenoid I measure 6-7 K ohms. Is this right?


Also, I checked voltages:
EPC solenoid at idle equals Battery Voltage (B+)

[777funk]

Anyone know the proper EPC solenoid resistance?

[777funk]

Ok I think the van is starting in 2nd, 3rd or 4th gear... I'm not sure. With the open circuit solenoid 1, that means that upon take off, no solenoids are engergized since the shift pattern is:
1st Gear - S1 NO S2
2nd Gear - S1 S2
3rd Gear - NO S1 S2
OD - NO S1 NO S2

The guy that rebuilt my trans thinks that the lack of grab is because it's starting off in a higher gear than first. He said the TQ Conv. is allowing slipage so it can start in a high gear (probably 3 or 4).

But I don't know if this is it or not.